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I have a stock 2008 trx450r I've been having some carb issues with a steady hold in the throttle you can hear it sputtering and it die's the second you let off the throttle and it will not idle the only time it will idle is with the choke on I've taken it apart and cleaned the jets but its still having the same problems,i thought maybe somehow the jets could have a little dirt i missed clogging it up but i don't think that's the case, any suggestions on a fix ? Thanks in advance.
 

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Did you turn the idle up? Spec is 1,700 rpm at idle.
Yeah I've messed around with the idle but no matter what i turn it to it still just stalls on its face the second i let off the throttle
 

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I see this a lot. I can tell you either you have way to large of a Pilot Jet or the Air Screw is adjusted way to far in or way to far out. Common issue when people take a carburetor apart on these they will remove the Idle Air Screw and not think about how many turns it was in or out or some cases people have even tried to install a bigger pilot jet or something. I've also seen the screws fall out and it's popping and running hot as hell during idle or won't idle.


1. Assuming you never took apart the carburetor first check to make sure that the Air Screw is still in place.

2. Assuming you did try and re jet it put the most previous Pilot Jet back in. 9 times out of 10 you never even need to replace the Pilot Jet when jetting a carburetor.


3. Now assuming all above is good... Best thing to do is to turn the Idle Screw up till you can get it idling (don't confuse this with the Air Screw) see if you can get it to idle with out having to hold the throttle.... Now with the idle Adjuster knob turned up (Assuming it's idling) you need to turn that Air Screw OUT until you hear the engine RPM's drop at this point turn the idle knob down as far as you can till it stalls and then turn the idle u a little bit and see if it fires up nicely with no throttle and it should idle nicely along with a good throttle response.
 

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What about auto decompression you know anything about this
If the Decompression lifter is out of Adjustment usually it will back fire when you kick it over, or it will be hard to start or to hard to push the kick starter down.
 

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If the Decompression lifter is out of Adjustment usually it will back fire when you kick it over, or it will be hard to start or to hard to push the kick starter down.
Yea it backfires once or twice but its just turning over hard to start
 

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And its a 2008 auto decompression
Oh okay the 2008 Auto Decompressor is not adjustable unfortunately. Have to tried to re jet the carburetor recently? Have you touched any air screws etc?
 

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Oh okay the 2008 Auto Decompressor is not adjustable unfortunately. Have to tried to re jet the carburetor recently? Have you touched any air screws etc?
Nah haven't touched carb its getting gas n jets are clean when I checked ..I messed with air screw to see if that help but it didnt
 

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Nah haven't touched carb its getting gas n jets are clean when I checked ..I messed with air screw to see if that help but it didnt
I would adjust the idle down as low as it will go and adjust the air screw in till the quad stalls and back it out half a turn start it back up and see how it runs again.
 

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I would adjust the idle down as low as it will go and adjust the air screw in till the quad stalls and back it out half a turn start it back up and see how it runs again.
Won't start just turns over and tries to crank shudders a few times like its about to start then just turns over
 
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